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arXiv 1602.09131astro-ph.GA
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Seyfert星系的中红外干涉测量:对标准模型的修正

Mid-infrared interferometry of Seyfert galaxies: Challenging the Standard Model

N. López-Gonzaga, W. Jaffe

摘要:

目的:我们的目标是找到环面模型,解释所观察到的活动星系核(AGN)的高分辨率中红外(MIR)测量。我们的目标是确定环核尘埃环境的一般性质。研究方法:我们使用的MIR干涉仪数据的样本AGN提供的仪器ESTA/VLTI,并按照统计方法比较观测到的分布的干涉数据的分布计算从cluaptorus模型。我们主要检验了塞弗特星系的多样性是否可以用标准模型的思想来描述。除了视线(LOS)的影响,我们进行了不同的实现相同的模型,包括可能的变化所造成的随机性质的尘埃模型。结果如下:我们发现,我们的整个样本的活动星系核,其中包含两个塞弗特类型,不能解释仅仅是一个倾斜效应,包括云的随机变化。相反,我们发现,每个子集的塞弗特型可以解释不同的模型,其中填充因子的内半径似乎是最大的差异。对于I型物体,我们发现大约三分之二的物体也可以用类似于II型物体的尘埃环面来描述。对于剩下的三分之一,使用具有高填充因子的模型无法找到良好的描述,而我们发现具有低填充因子的模型拟合良好。结论:在我们的模型假设,我们没有找到一个单一的一组模型参数,可以同时解释所有21个活动星系核与LOS效应和随机变化的MIR数据。我们的结论是,至少需要两个不同的云配置模型的差异,在塞弗特星系,体积填充因子的差异约5-10倍。不能排除这两种类型之间的连续过渡。

英文摘要:

Aims: We aim to find torus models that explain the observed high-resolution mid-infrared (MIR) measurements of active galactic nuclei (AGN). Our goal is to determine the general properties of the circumnuclear dusty environments. Methods: We used the MIR interferometric data of a sample of AGNs provided by the instrument MIDI/VLTI and followed a statistical approach to compare the observed distribution of the interferometric data with the distributions computed from clumpy torus models. We mainly tested whether the diversity of Seyfert galaxies can be described using the Standard Model idea. In addition to line-of-sight (LOS) effects, we performed different realizations of the same model to include possible variations that are caused by the stochastic nature of the dusty models. Results: We find that our entire sample of AGNs, which contains both Seyfert types, cannot be explained merely by an inclination effect and by including random variations of the clouds. Instead, we find that each subset of Seyfert type can be explained by different models, where the filling factor at the inner radius seems to be the largest difference. For type I objects we find that about two thirds of our objects could also be described using a dusty torus similar to the type II objects. For the remaining third, it was not possible to find a good description using models with high filling factors, while we found good fits with models with low filling factors. Conclusions: Within our model assumptions, we did not find one single set of model parameters that could simultaneously explain the MIR data of all 21 AGN with LOS effects and random variations alone. We conclude that at least two distinct cloud configurations are required to model the differences in Seyfert galaxies, with volume-filling factors differing by a factor of about 5-10. A continuous transition between the two types cannot be excluded.

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